diff options
Diffstat (limited to 'epan/dissectors/packet-rmt-fec.c')
| -rw-r--r-- | epan/dissectors/packet-rmt-fec.c | 367 |
1 files changed, 367 insertions, 0 deletions
diff --git a/epan/dissectors/packet-rmt-fec.c b/epan/dissectors/packet-rmt-fec.c new file mode 100644 index 00000000..044fe49a --- /dev/null +++ b/epan/dissectors/packet-rmt-fec.c @@ -0,0 +1,367 @@ +/* packet-rmt-fec.c + * Reliable Multicast Transport (RMT) + * FEC Building Block dissector + * Copyright 2005, Stefano Pettini <spettini@users.sourceforge.net> + * + * Forward Error Correction (ALC): + * ------------------------------- + * + * The goal of the FEC building block is to describe functionality + * directly related to FEC codes that is common to all reliable content + * delivery IP multicast protocols, and to leave out any additional + * functionality that is specific to particular protocols. + * + * References: + * RFC 3452, Forward Error Correction Building Block + * RFC 3695, Compact Forward Error Correction (FEC) Schemes + * Simple XOR, Reed-Solomon, and Parity Check Matrix-based FEC Schemes draft-peltotalo-rmt-bb-fec-supp-xor-pcm-rs-00 + * IANA RMT FEC parameters (http://www.iana.org/assignments/rmt-fec-parameters) + * + * Wireshark - Network traffic analyzer + * By Gerald Combs <gerald@wireshark.org> + * Copyright 1998 Gerald Combs + * + * SPDX-License-Identifier: GPL-2.0-or-later + */ + +#include "config.h" + +#include <epan/packet.h> +#include <epan/expert.h> +#include <epan/proto_data.h> +#include "packet-rmt-common.h" + +void proto_register_rmt_fec(void); + +static int proto_rmt_fec = -1; + +static int hf_encoding_id = -1; +static int hf_instance_id = -1; +static int hf_sbn = -1; +static int hf_sbn_with_mask = -1; +static int hf_sbl = -1; +static int hf_esi = -1; +static int hf_esi_with_mask = -1; +static int hf_fti_transfer_length = -1; +static int hf_fti_encoding_symbol_length = -1; +static int hf_fti_max_source_block_length = -1; +static int hf_fti_max_number_encoding_symbols = -1; +static int hf_fti_num_blocks = -1; +static int hf_fti_num_subblocks = -1; +static int hf_fti_alignment = -1; + +static int ett_main = -1; + +static expert_field ei_fec_encoding_id = EI_INIT; + +typedef struct fec_packet_data +{ + guint8 instance_id; + +} fec_packet_data_t; + + +/* String tables */ +const value_string string_fec_encoding_id[] = +{ + { 0, "Compact No-Code" }, + { 1, "Raptor" }, + { 2, "Reed-Solomon Codes over GF(2^^m)" }, + { 3, "LDPC Staircase Codes" }, + { 4, "LDPC Triangle Codes" }, + { 5, "Reed-Solomon Codes over GF(2^^8)" }, + { 6, "RaptorQ Code" }, + /* 7-127 Unassigned */ + { 128, "Small Block, Large Block and Expandable FEC Codes" }, + { 129, "Small Block Systematic FEC Codes" }, + { 130, "Compact FEC Codes" }, + /* 131-255 Unassigned */ + { 0, NULL } +}; + +/* Dissection */ +/* ---------- */ + +/* Decode an EXT_FTI extension and fill FEC array */ +void fec_decode_ext_fti(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, int offset, guint8 encoding_id) +{ + guint64 transfer_length; + fec_packet_data_t *fec_data; + guint8 instance_id = 0; + proto_item *ti; + + if (encoding_id == 6){ + /* Raptor Q uses 40-bit transfer length */ + transfer_length = tvb_get_ntoh40(tvb, offset+2); + } + else { + /* Decode 48-bit length field */ + transfer_length = tvb_get_ntoh48(tvb, offset+2); + } + + if (encoding_id >= 128) + { + instance_id = (guint8) tvb_get_ntohs(tvb, offset+8); + + /* Decode FEC Instance ID */ + fec_data = wmem_new0(wmem_file_scope(), fec_packet_data_t); + fec_data->instance_id = instance_id; + + p_add_proto_data(wmem_file_scope(), pinfo, proto_rmt_fec, 0, fec_data); + } + + if (encoding_id == 6){ + /* Raptor Q uses 40-bit transfer length */ + proto_tree_add_uint64(tree, hf_fti_transfer_length, tvb, offset+2, 5, transfer_length); + } + else { + proto_tree_add_uint64(tree, hf_fti_transfer_length, tvb, offset+2, 6, transfer_length); + ti = proto_tree_add_item(tree, hf_instance_id, tvb, offset+8, 2, ENC_BIG_ENDIAN); + if ((encoding_id < 128) && (encoding_id != 0)) { + expert_add_info(pinfo, ti, &ei_fec_encoding_id); + } + } + + switch (encoding_id) + { + case 1: + proto_tree_add_item(tree, hf_fti_encoding_symbol_length, tvb, offset+10, 2, ENC_BIG_ENDIAN); + proto_tree_add_item(tree, hf_fti_num_blocks, tvb, offset+12, 2, ENC_BIG_ENDIAN); + proto_tree_add_item(tree, hf_fti_num_subblocks, tvb, offset+14, 1, ENC_BIG_ENDIAN); + proto_tree_add_item(tree, hf_fti_alignment, tvb, offset+15, 1, ENC_BIG_ENDIAN); + break; + + case 6: + proto_tree_add_item(tree, hf_fti_encoding_symbol_length, tvb, offset+8, 2, ENC_BIG_ENDIAN); + proto_tree_add_item(tree, hf_fti_num_blocks, tvb, offset+10, 1, ENC_BIG_ENDIAN); + proto_tree_add_item(tree, hf_fti_num_subblocks, tvb, offset+11, 2, ENC_BIG_ENDIAN); + proto_tree_add_item(tree, hf_fti_alignment, tvb, offset+13, 1, ENC_BIG_ENDIAN); + break; + + case 0: + case 2: + case 128: + case 130: + proto_tree_add_item(tree, hf_fti_encoding_symbol_length, tvb, offset+10, 2, ENC_BIG_ENDIAN); + proto_tree_add_item(tree, hf_fti_max_source_block_length, tvb, offset+12, 4, ENC_BIG_ENDIAN); + break; + + case 129: + proto_tree_add_item(tree, hf_fti_encoding_symbol_length, tvb, offset+10, 2, ENC_BIG_ENDIAN); + proto_tree_add_item(tree, hf_fti_max_source_block_length, tvb, offset+12, 2, ENC_BIG_ENDIAN); + proto_tree_add_item(tree, hf_fti_max_number_encoding_symbols, tvb, offset+14, 2, ENC_BIG_ENDIAN); + break; + + case 132: + proto_tree_add_item(tree, hf_fti_encoding_symbol_length, tvb, offset+10, 2, ENC_BIG_ENDIAN); + proto_tree_add_item(tree, hf_fti_max_source_block_length, tvb, offset+12, 4, ENC_BIG_ENDIAN); + proto_tree_add_item(tree, hf_fti_max_number_encoding_symbols, tvb, offset+16, 4, ENC_BIG_ENDIAN); + break; + } +} + +/* Dissect a FEC header: + * fec - ptr to the logical FEC packet representation to fill + * hf - ptr to header fields array + * ett - ptr to ett array + * prefs - ptr to FEC prefs array + * tvb - buffer + * pinfo - packet info + * tree - tree where to add FEC header subtree + * offset - ptr to offset to use and update + */ +static int +dissect_fec(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data) +{ + proto_item *ti; + proto_tree *fec_tree; + guint offset = 0; + fec_data_exchange_t *fec = (fec_data_exchange_t*)data; + guint8 encoding_id = 0; + fec_packet_data_t *packet_data = (fec_packet_data_t*)p_get_proto_data(wmem_file_scope(), pinfo, proto_rmt_fec, 0); + + if (fec != NULL) + { + encoding_id = fec->encoding_id; + } + + /* Create the FEC subtree */ + ti = proto_tree_add_item(tree, proto_rmt_fec, tvb, offset, -1, ENC_NA); + fec_tree = proto_item_add_subtree(ti, ett_main); + + proto_tree_add_uint(fec_tree, hf_encoding_id, tvb, offset, 0, encoding_id); + + if (encoding_id >= 128 && (packet_data != NULL)) + proto_tree_add_uint(fec_tree, hf_instance_id, tvb, offset, 0, packet_data->instance_id); + + switch (encoding_id) + { + case 0: + case 1: + case 130: + proto_tree_add_item(fec_tree, hf_sbn, tvb, offset, 2, ENC_BIG_ENDIAN); + proto_tree_add_item(fec_tree, hf_esi, tvb, offset+2, 2, ENC_BIG_ENDIAN); + + col_append_sep_fstr(pinfo->cinfo, COL_INFO, " ", "SBN: %u", tvb_get_ntohs(tvb, offset)); + col_append_sep_fstr(pinfo->cinfo, COL_INFO, " ", "ESI: 0x%X", tvb_get_ntohs(tvb, offset+2)); + + offset += 4; + break; + + case 2: + case 128: + case 132: + proto_tree_add_item(fec_tree, hf_sbn, tvb, offset, 4, ENC_BIG_ENDIAN); + proto_tree_add_item(fec_tree, hf_esi, tvb, offset+4, 4, ENC_BIG_ENDIAN); + + col_append_sep_fstr(pinfo->cinfo, COL_INFO, " ", "SBN: %u", tvb_get_ntohl(tvb, offset)); + col_append_sep_fstr(pinfo->cinfo, COL_INFO, " ", "ESI: 0x%X", tvb_get_ntohl(tvb, offset+4)); + + offset += 8; + break; + + case 3: + case 4: + proto_tree_add_item(fec_tree, hf_sbn_with_mask, tvb, offset, 4, ENC_BIG_ENDIAN); + proto_tree_add_item(fec_tree, hf_esi_with_mask, tvb, offset, 4, ENC_BIG_ENDIAN); + + col_append_sep_fstr(pinfo->cinfo, COL_INFO, " ", "SBN: %u", tvb_get_ntohl(tvb, offset) >> 20); + col_append_sep_fstr(pinfo->cinfo, COL_INFO, " ", "ESI: 0x%X", tvb_get_ntohl(tvb, offset) & 0xfffff); + + offset += 4; + break; + + case 6: + proto_tree_add_item(fec_tree, hf_sbn, tvb, offset, 1, ENC_BIG_ENDIAN); + proto_tree_add_item(fec_tree, hf_esi, tvb, offset+1, 3, ENC_BIG_ENDIAN); + + col_append_sep_fstr(pinfo->cinfo, COL_INFO, " ", "SBN: %u", tvb_get_guint8(tvb, offset)); + col_append_sep_fstr(pinfo->cinfo, COL_INFO, " ", "ESI: 0x%X", tvb_get_ntoh24(tvb, offset+1)); + + offset += 4; + break; + + case 129: + proto_tree_add_item(fec_tree, hf_sbn, tvb, offset, 4, ENC_BIG_ENDIAN); + proto_tree_add_item(fec_tree, hf_sbl, tvb, offset+4, 2, ENC_BIG_ENDIAN); + proto_tree_add_item(fec_tree, hf_esi, tvb, offset+6, 2, ENC_BIG_ENDIAN); + + col_append_sep_fstr(pinfo->cinfo, COL_INFO, " ", "SBN: %u", tvb_get_ntohl(tvb, offset)); + col_append_sep_fstr(pinfo->cinfo, COL_INFO, " ", "ESI: 0x%X", tvb_get_ntohs(tvb, offset+6)); + + offset += 8; + break; + } + + return offset; +} + +void proto_register_rmt_fec(void) +{ + static hf_register_info hf[] = { + { &hf_encoding_id, + { "FEC Encoding ID", "rmt-fec.encoding_id", + FT_UINT8, BASE_DEC, VALS(string_fec_encoding_id), 0x0, + NULL, HFILL } + }, + { &hf_instance_id, + { "FEC Instance ID", "rmt-fec.instance_id", + FT_UINT8, BASE_DEC, NULL, 0x0, + NULL, HFILL } + }, + { &hf_sbn, + { "Source Block Number", "rmt-fec.sbn", + FT_UINT32, BASE_DEC, NULL, 0x0, + NULL, HFILL } + }, + { &hf_sbn_with_mask, + { "Source Block Number", "rmt-fec.sbn", + FT_UINT32, BASE_DEC, NULL, 0xFFF00000, + NULL, HFILL } + }, + { &hf_sbl, + { "Source Block Length", "rmt-fec.sbl", + FT_UINT32, BASE_DEC, NULL, 0x0, + NULL, HFILL } + }, + { &hf_esi, + { "Encoding Symbol ID", "rmt-fec.esi", + FT_UINT32, BASE_HEX, NULL, 0x0, + NULL, HFILL } + }, + { &hf_esi_with_mask, + { "Encoding Symbol ID", "rmt-fec.esi", + FT_UINT32, BASE_HEX, NULL, 0x000FFFFF, + NULL, HFILL } + }, + { &hf_fti_transfer_length, + { "Transfer Length", "rmt-fec.fti.transfer_length", + FT_UINT64, BASE_DEC, NULL, 0x0, + NULL, HFILL } + }, + { &hf_fti_encoding_symbol_length, + { "Encoding Symbol Length", "rmt-fec.fti.encoding_symbol_length", + FT_UINT32, BASE_DEC, NULL, 0x0, + NULL, HFILL } + }, + { &hf_fti_max_source_block_length, + { "Maximum Source Block Length", "rmt-fec.fti.max_source_block_length", + FT_UINT32, BASE_DEC, NULL, 0x0, + NULL, HFILL } + }, + { &hf_fti_max_number_encoding_symbols, + { "Maximum Number of Encoding Symbols", "rmt-fec.fti.max_number_encoding_symbols", + FT_UINT32, BASE_DEC, NULL, 0x0, + NULL, HFILL } + }, + { &hf_fti_num_blocks, + { "Number of Source Blocks", "rmt-fec.fti.num_blocks", + FT_UINT16, BASE_DEC, NULL, 0x0, + NULL, HFILL } + }, + { &hf_fti_num_subblocks, + { "Number of Sub-Blocks", "rmt-fec.fti.num_subblocks", + FT_UINT16, BASE_DEC, NULL, 0x0, + NULL, HFILL } + }, + { &hf_fti_alignment, + { "Symbol Alignment", "rmt-fec.fti.alignment", + FT_UINT8, BASE_DEC, NULL, 0x0, + NULL, HFILL } + } + }; + + /* Setup protocol subtree array */ + static gint *ett[] = { + &ett_main, + }; + + static ei_register_info ei[] = { + { &ei_fec_encoding_id, { "rmt-fec.encoding_id.not0", PI_PROTOCOL, PI_WARN, "FEC Encoding ID < 128, should be zero", EXPFILL }}, + }; + + expert_module_t* expert_rmt_fec; + + /* Register the protocol name and description */ + proto_rmt_fec = proto_register_protocol("Forward Error Correction (FEC)", "RMT-FEC", "rmt-fec"); + register_dissector("rmt-fec", dissect_fec, proto_rmt_fec); + + /* Required function calls to register the header fields and subtrees used */ + proto_register_field_array(proto_rmt_fec, hf, array_length(hf)); + proto_register_subtree_array(ett, array_length(ett)); + expert_rmt_fec = expert_register_protocol(proto_rmt_fec); + expert_register_field_array(expert_rmt_fec, ei, array_length(ei)); +} + +/* + * Editor modelines - https://www.wireshark.org/tools/modelines.html + * + * Local variables: + * c-basic-offset: 4 + * tab-width: 8 + * indent-tabs-mode: nil + * End: + * + * ex: set shiftwidth=4 tabstop=8 expandtab: + * :indentSize=4:tabSize=8:noTabs=true: + */ |